1. Sliding Filament Theory Review

2. The “Actors” Acetylcholine Actin ATP Ca+ ions Myosin heads Na+/K+ ions
Troponin
Tropomyosin
Sarcoplasmic reticulum
Z-line
The “Actors”

3. Binds to sarcolemma
Opens Na+/K+ gated ion channels
Acetylcholine

4. Pulled by myosin
Attaches to Z-line
Actin

5. ATP Energizes the power stroke of myosin head
Disconnects the myosin cross bridge from the binding site on actin.
Fuels the pump that actively transports calcium ions back into the sarcoplasmic reticulum.
ATP

6. Bind to troponin
Help expose binding sites on actin
Ca+ ions

7. Powered by ATP, pull actin filaments closer together
Myosin heads

8. Na+/K+ Ions Depolarize muscle cell
Cause Ca+ ions to leave sarcoplasmic reticulum
Na+/K+ Ions

9. Troponin Binds to tropomyosin
When Ca+ present, helps slide tropomyosin off binding sites
Troponin

10. Covers binding sites on actin where myosin heads bind
Tropomyosin

11. Sarcoplasmic Reticulum
Storage of Ca+ ions
Released during depolarization
Sarcoplasmic Reticulum

12. Z-lines Pulled together during contraction
Attached to actin myofilaments
Z-lines

13. Click here to see a quick animation review…

14. Write a script for the “Actors”
Acetylcholine
Actin
ATP
Ca+ ions
Myosin heads
Na + /K + ions
Troponin
Tropomyosin
Sarcoplasmic reticulum
Z-line
Write a script for the “Actors”